Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thu sach » tu sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
sang ma » tang ma, sang tao, mang may
va hanh » van hanh, va thanh, va danh
hai dat » cai dat, hoi dat, hai dan
nang ma » tang ma, nang cao, mang may
van hai » van ha, van chat, van hanh
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (thuat sach)) ky ((sang ma) OR (nang ma)) hoi. hieu van hai dat va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) ky ((sang ma) OR (nang ma)) hoi. hieu van hai dat va hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuat sach)) ky ((sang ma) OR (nang ma)) hoi. hieu van hai dat va hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuat sach)) ky ((sang ma) OR (nang ma)) hoi. hieu van hai dat va hanh vi cua vat*.